/Engine/Source/Editor/UnrealEd/Public/SCommonEditorViewportToolbarBase.h
Merges the extender list from the host with the specified extender and returns the results.
[TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FExtender](API\Runtime\Slate\Framework\MultiBox\FExtender) > GetCombinedExtenderList ( [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [FExtender](API\Runtime\Slate\Framework\MultiBox\FExtender) > MenuExtender ) const